KT-33903: consider imports from objects when removing descriptors duplicates

- `ImportedFromObjectCallableDescriptor` and descriptors in general do
not have consistent `equals`,  which leads to duplication in completion
when multiple functions from objects are imported, or when function is
visible in some scope both implicitly and by import (see KT33903_1.kt)
- ^KT-33903 Fixed

idea/idea-completion/testData/basic/common/KT33903_1.kt

@@ -0,0 +1,13 @@
+import Obj.foo
+import Obj.foo
+
+object Obj {
+    fun Any.foo() {}
+
+    fun usage() {
+        Any().foo<caret>
+    }
+}
+
+// EXIST: foo
+// NUMBER: 1

idea/idea-completion/testData/basic/common/KT33903_2.kt

@@ -0,0 +1,13 @@
+import Obj.foo
+import Obj.foo
+
+object Obj {
+    fun Any.foo() {}
+}
+
+fun usage() {
+    Any().foo<caret>
+}
+
+// EXIST: foo
+// NUMBER: 1